The present invention relates to a recording/reproducing method and a disc recording/reproducing apparatus for recording/reproducing data onto/from a recording medium capable of recording digital data.
Optical discs having large capacity such as a DVD (Digital Versatile Disc: registered trademark) and the like have been widely prevailing among recent disc recording/reproducing apparatuses.
Optical disc media (recording media) such as a DVD and the like as described above include various types, e.g., ROM (Read Only Memory) type media which are sold with contents prerecorded thereon, RW (Rewritable) type media on which data can be overwritten many times, and R (Recordable) type media into which data can be written only once.
These media each have a so-called management area existing in a preserved area on the disc, to facilitate search for data recorded internally. Recording management information to manage recording states of user data is recorded in the management area.
When a disc is inserted, an optical disc recording/reproducing apparatus first reads data (recording management information) written in the management area. The management area is thus used to read how much user data are recorded at what position on the disc, and to perform reproduction and additional writing at high speed. If there is no management area of this kind (e.g., sequential media such as tapes), no measure is provided to know where user data is written. Therefore, data have to be reproduced from the beginning of data to search for some data.
In RW type media, the management area is updated by overwriting data (management information) every time internal data are updated. However, if a recorded portion thereof does not allow writing due to a damage on the disc or due to excessive overwriting beyond an allowable number of times of overwriting (this is called a defect), recording is tried by changing the recording position.
On the other side, in R type media, overwriting is impossible due to the nature of media. Therefore, a larger management area is preserved. Every time management information is updated from the head of the area, new management information is written additionally.
In case of reproducing data recorded on media of these kinds, data fed from an optical pickup are subjected to waveform shaping by an equalization circuit and there after to error correction. Then, the data are stored into a buffer memory, and are sent to a host computer or video player through an external I/F.
In each of media like optical discs, the whole medium is divided into sectors each having a predetermined data quantity. Every one of the sectors is assigned at a physical address. By using these addresses, the disc area is divided into a user data recording area and the other area in accordance with purposes of use. A recording area for the aforementioned management information exists in the other area than the user data.
If the management information is broken by some factor to become unreadable, user data itself cannot be read. However, up to what position user data have been recorded can be determined by providing a circuit which detects presence or absence of an RF signal recorded on the disc face and by reproducing data from the head address of user data.
For example, Japanese Patent Application Laid-Open Publication No. 2003-228853 discloses an optical disc apparatus and a control method thereof. This apparatus records data on a DVD-R as a typical example of a writable optical disc on which data can be written only once, i.e., a so-called write-once optical disc.